MPGS and Skyrocketing Gas Prices

Pittdawg

Original poster
Member
Dec 5, 2011
538
For all of you not located in CA. you may not be aware that due to refinery fires, "summer blend' gas and other factors gas prices have skyrocketed. Were talking $4.80 a gallon averages. In any event, due to the high prices I decided to perform and experiment. Basically, how good of mpgs could the ol gal get if I drove her like a little old lady from Pasadena. Well, I just finished a tank where I accelerated from a stop so low, and kept the rpms below 2000 rpms virtually the whole tank that people were flooring it past me, cutting me off, flipping me off, etc. It was actually kinda amusing in a way. To make a long story short, my avg. of 15.8 mpgs went up to 17.8 mpgs, an exact 2 mpg better difference. This is in mixed driving but with a decent amount of traffic for the highway portion. Just thought I would share.
 

ItsOnVoy

Member
Nov 21, 2011
2,401
I personally could never drive like that haha not worth saving a couple of mpg but good to know. I was told no higher then 3000 rpms and you will get what you should get getting.
 

Mooseman

Moderator
Dec 4, 2011
25,335
Ottawa, ON
I doubled my MPGs. I started using my son's Honda Accord to go to work. $100/week to go to work was killing me.
 

ItsOnVoy

Member
Nov 21, 2011
2,401
Mooseman said:
I doubled my MPGs. I started using my son's Honda Accord to go to work. $100/week to go to work was killing me.

thats a lot!! Right now I put a good $50 a week not as bad but bad enough for a college student!
 

ksimm92

Member
Apr 28, 2012
166
I try and keep my rpm's around 2,500 , and usually get around 16-17 mpg. I drive probably 60% highway and 40% city. The highest Ive ever gotten was 19.5-20 all highway.
 

cmatb08

Member
Jun 3, 2012
101
We are doin about 65-100 a week depending what gas station and if the Tb wants to idle at a 1000rpm or not. 90% of the time she idled at 1000rpm which kills us! That's with my wife driving, I would go through it a lil faster :biggrin:
 

meerschm

Member
Aug 26, 2012
1,079
so how many PSI in your tires?
 

bdorsch44

Member
Apr 21, 2012
10
I tell ya, delivering pizza's in a Trailblaze can be a real doozie. I was at around 12.3 but after cleaning the throttle body, new air filter and running seafoam through the system, I'm between 15.5 and 16.0:smile:
 

meerschm

Member
Aug 26, 2012
1,079
limequat said:
Because I haven't said it yet today, "AR5 Swap". Probably good for 2-3 mpg.

have you done this on an I6 TB?
 

Jkust

Member
Dec 4, 2011
946
I tried this when I got my 9-7 last year. I have almost all highway so tried to keep the rpms low and stay at the 60mph limit in the center lane. I couldn't maintain going so slow after everyone would pass me at 75 the whole way to work those first weeks. The mpg's were better however not quite 2 better.
 

ItsOnVoy

Member
Nov 21, 2011
2,401
cmatb08 said:
We have 35 or 40psi and the tires are a 275/45R20

usually up to 36psi is what you want, 40 is a bit much
 

JerryIrons

Member
Dec 20, 2011
434
I get right about 16 mpg in my I6. This year I changed out a bad thermostat, bad o2 sensor in front, and now I get 16 mpg... :wink:
 

SAR85

Member
Jan 31, 2012
74
JerryIrons said:
I get right about 16 mpg in my I6. This year I changed out a bad thermostat, bad o2 sensor in front, and now I get 16 mpg... :wink:

So it made no difference?
 

Pittdawg

Original poster
Member
Dec 5, 2011
538
When I bought my Envoy (used with 37K miles) and it was all stock I averaged 16.5 mpgs in "mixed" L.A. driving. I specify "mixed" L.A. because it is not fair to characterize L.A. freeways as "highway" driving as there is a lot of traffic and stop and go more like city driving. In any event, the first mod I did was the Volant CAI. No real difference in mpgs, maybe small loss down to 16 mpgs. The next mod I did was resonator delete. No discernible difference in mpgs. Next mod I did was pcmforless tune. After a couple tanks of giving it the boot, and back to normal driving, my avg went from 16mpgs to about 16.8 mpgs. The next mod I did was ported and polished throttle body. Mpgs went back down to stock level of 16.5 mpgs.

Next mod was 265/65/17's and 4.10 gears. My mpgs dropped to about 15.5. Don't know if it was heavier wider rolling stock or gears or both but I definately lost at least 1 mpg. Next mod was custom catback exhaust. Lost about 1 mpg initially (14.5 mpgs :hissyfit:) but after computer re-learned and the install of smaller rear resonator mpg came back up to about 15.8 where it is now, unless I baby it. I bet if I had stock size tires on I'd be right around the stock level of 16.5 mpgs. I can say my truck is MUCH faster than stock so the .7 mpg loss is worth it to me even with these ridiculous gas prices.

We'll see if the ported heads affect mpgs positively or negatively. Stay tuned.
 

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